Zantedeschia aethiopica spathe undergoes whitening displaying the common features of foliar senescence. After pollination, the spathe region surrounding the fruits undergo regreening, thus reacquiring photosynthetic ability. In this work, changes in peroxisomal metabolism were studied in what concerns key-enzymes of glyoxylate and glycolate pathways. Putative roles for CAT1 and CAT2 are discussed.
Material and Methods: Spathes during the time course of senescence and regreening were harvested from field-grown plants. The content in hydrogen peroxide (H2O2) followed Loreto et al (2001). Catalase activity was determined by following the decomposition of H2O2 at 240 nm (Aebi, 1983). Northern analysis was performed using Z. aethiopica Cat1 (AF207906) and Cat2 (AF332973) cDNAs as homologous probes. The activity of the glyoxysomal-marker enzyme isocitrate lyase (ICL) and leaf-type peroxisomal marker enzyme hydroxypyruvate reductase (HPR) were determined according to Zelitch (1988) and Liang et al. (1984), respectively.
Results and Conclusions: Changes in ICL and HPR activitiy suggest that during Z. aethiopica spathe development there is an induction of glyoxysomal metabolism during the late stages of whitening, followed by the induction of leaf-type peroxisome metabolism during regreening. In addition...

This work describes the purification and characterization of enzymes that exhibit β-d-xylosidase activity in stem tissues of Arabidopsis. This is the first detailed investigation that concerns the characterization of catalytic properties and sequence identity of enzymes with β-d-xylosidase activities in a dicotyledonous plant. Three different enzymes, ARAf, XYL4, and XYL1 with apparent molecular masses of 75, 67, and 64 kD, respectively, were purified to homogeneity. ARAf was identified as a putative α-l-arabinofuranosidase, and XYL4 and XYL1 as putative β-d-xylosidases using matrix-assisted laser-desorption ionization time of flight. ARAf belongs to family 51 and XYL4 and XYL1 to family 3 of glycoside hydrolases. ARAf and XYL1 have highest specificity for p-nitrophenyl-α-l-arabinofuranoside and XYL4 for p-nitrophenyl-β-d-xylopyranoside and natural substrates such as xylobiose and xylotetraose. XYL4 was shown to release mainly d-Xyl from oat spelt xylan, rye arabinoxylan, wheat arabinoxylan, and oligoarabinoxylans. ARAf and XYL1 can also release d-Xyl from these substrates but less efficiently than XYL4. Moreover, they can also release l-Ara from arabinoxylans and arabinan. Overall, the results indicate that XYL4 possesses enzymatic specificity characteristic for a β-d-xylosidase...

Widespread use of the endocrine disrupting chemical bisphenol A (BPA) in consumer products has resulted in nearly continuous human exposure. In rodents, low-dose exposures have been reported to adversely affect two distinct stages of oogenesis in the developing ovary: the events of prophase at the onset of meiosis in the fetal ovary and the formation of follicles in the perinatal ovary. Because these effects could influence the reproductive longevity and success of the exposed individual, we conducted studies in the rhesus monkey to determine whether BPA induces similar disturbances in the developing primate ovary. The routes and levels of human exposure are unclear; hence, two different exposure protocols were used: single daily oral doses and continuous exposure via subdermal implant. Our analyses of second trimester fetuses exposed at the time of meiotic onset suggest that, as in mice, BPA induces subtle disturbances in the prophase events that set the stage for chromosome segregation at the first meiotic division. Our analyses of third-trimester fetuses exposed to single daily oral doses during the time of follicle formation revealed an increase in multioocyte follicles analogous to that reported in rodents. However, two unique phenotypes were evident in continuously exposed animals: persistent unenclosed oocytes in the medullary region and small...

Transgenic insect-resistant cotton has been released into the environment for more than a decade in China to effectively control the cotton bollworm (Helicoverpa armigera) and other Lepidoptera. Because of concerns about undesirable ecological side-effects of transgenic crops, it is important to monitor the potential environmental impact of transgenic insect-resistant cotton after commercial release. Our 2-year study included 1 cotton field where non-transgenic cotton had been planted continuously and 2 other cotton fields where transgenic insect-resistant cotton had been planted for different lengths of time since 1997 and since 2002. In 2 consecutive years (2009 and 2010), we took soil samples from 3 cotton fields at 4 different growth stages (seedling, budding, boll-forming and boll-opening stages), collected soil nematodes from soil with the sugar flotation and centrifugation method and identified the soil nematodes to the genus level. The generic composition, individual densities and diversity indices of the soil nematodes did not differ significantly between the 2 transgenic cotton fields and the non-transgenic cotton field, but significant seasonal variation was found in the individual densities of the principal trophic groups and in the diversity indices of the nematodes in all 3 cotton fields. The study used a comparative perspective to monitor the impact of transgenic insect-resistant cotton grown in typical ‘real world’ conditions. The results of the study suggested that more than 10 years of cultivation of transgenic insect-resistant cotton had no significant effects–adverse or otherwise–on soil nematodes. This study provides a theoretical basis for ongoing environmental impact monitoring of transgenic plants.

This thesis explores the wrinkling and sagging behavior of thin viscous Newtonian sheets and filaments motivated by analogous scenarios in elasticity. These problems involve dynamic free boundaries and geometric nonlinearities but use simple physics. The first problem examined concerns an annular viscous sheet subjected to torsional shearing which consequently develops spiral wrinkles. Examination of the behavior of this system leads to a scaling of the Stokes equations for zero Reynolds number flow resulting in a reduced order mathematical model for the evolution of the sheet that includes the effects of gravity and surface tension. Linear stability analysis yields the most unstable modes for wrinkling of the sheet and their associated growth rates at onset which agree with experimental observations. In the limit of a narrow annular gap, the problem reduces to that of a sheared rectilinear sheet. Interestingly, this Couette problem shows instabilities even in the zero Reynolds number limit. The second problem examined concerns the sagging of a horizontal viscida (fluid filament) under the influence of gravity. Resistance of the viscida to bending controls the initial phase of deformation, while resistance to stretching begins to play a principal role in later stages. At very late times the process resembles droplet break-off from two thin filaments.; by Jeremy Alan Teichman.; Thesis (Ph. D.)--Massachusetts Institute of Technology...

Coal is widely relied upon as a fuel for electric power generation, and pressure is increasing to limit emissions of the CO2 produced during its combustion because of concerns over climate change. In order to continue the use of coal without emitting CO2, low cost technologies must be developed for capturing CO2 from power plants. Current CO2 capture technology is expensive, both in terms of capital and operating cost, so research and development efforts will be heavily relied upon to improve the economic profile of the technologies. With scarce resources available for R&D, and a number or different technologies competing for these funds, efforts must be prudently prioritized in order for successful advancements to be realized. This thesis assesses the state-of-the-art CO2 capture technologies available today, as well as the leading technology options for improvement. It also examines types of R&D, government and industry roles in R&D efforts, and methods and tools for managing these efforts. From these analyses, qualitative conclusions about how to prioritize CO2 capture technology R&D efforts to ensure advancement are offered.; (cont.) There are three technological pathways for CO2 capture - post-combustion, oxy-fired, and pre-combustion capture - and several technology options for improvement in each pathway. There are currently no clear winners...

When crosscutting concerns identification is performed from the beginning of
development, on the activities involved in requirements engineering, there are many
gains in terms of quality, cost and efficiency throughout the lifecycle of software
development. This early identification supports the evolution of requirements,
detects possible flaws in the requirements specification, improves traceability among
requirements, provides better software modularity and prevents possible rework.
However, despite these several advantages, the crosscutting concerns identification
over requirements engineering faces several difficulties such as the lack of
systematization and tools that support it. Furthermore, it is difficult to justify why
some concerns are identified as crosscutting or not, since this identification is, most
often, made without any methodology that systematizes and bases it. In this context,
this paper proposes an approach based on Grounded Theory, called GT4CCI, for
systematizing and basing the process of identifying crosscutting concerns in the
initial stages of the software development process in the requirements document.
Grounded Theory is a renowned methodology for qualitative analysis of data.
Through the use of GT4CCI it is possible to better understand...

International migration offers
individuals and their families the potential to experience
immediate and large gains in their incomes, and offers a
large number of other positive benefits to the sending
communities and countries. However, there are also concerns
about potential costs of migration, including concerns about
trafficking and human rights, a desire for remittances to be
used more effectively, and concerns about externalities from
skilled workers being lost. As a result there is increasing
interest in policies which can enhance the development
benefits of international migration and mitigate these
potential costs. This paper provides a critical review of
recent research on the effectiveness of these policies at
three stages of the migration process: pre-departure, during
migration, and directed toward possible return. The existing
evidence base suggests some areas of policy success:
bilateral migration agreements for countries whose workers
have few other migration options, developing new savings and
remittance products that allow migrants more control over
how their money is used...

An evaluation has been made of two different techniques which could prove valuable for Naval refrigeration needs in the future. The first is electrohydrodynamic (EHD) enhancement of pool boiling and condensation heat transfer; this has been shown to provide significant enhancements for both modes of heat transfer under certain conditions and could provide increases in efficiency of present vapor-compression systems. EHD techniques are quite advanced and prototype condenser and evaporator bundles are currently being tested. The second technique is an alternative refrigeration technology called thermoacoustic refrigeration; alternative technologies have become increasingly attractive over recent years due to environmental concerns over CFCs. Thermoacoustic refrigeration uses acoustic power to pump heat from a low temperature source to a high temperature sink. It is still in the early stages of development and can presently accommodate only small thermal loads. However, its general principles of operation have been proven and its resent capacity and efficiency limitations are not seen as a problem in the long term. Electrohydrodynamic Enhancement, Boiling and Condensation, Thermoacoustic Refrigeration

non-peer-reviewed; Aims: Early intervention in youth mental health is increasingly viewed as easier, cheaper and more effective than traditional approaches to care. GPs, as the healthcare professional most often consulted by young people, have a central role in early detection of youth mental health and addiction disorders. However, international data suggests many young people have concerns bringing these issues to their GP, and GPs themselves experience difficulty identifying and treating mental health issues. The aim of this study is to gain an understanding of the experience of youth mental health and addiction treatment in two deprived urban areas to inform future early intervention practice development.
Methods: Semi-structured interviews were recorded with 37 healthcare professionals. Inductive thematic analysis was carried out using QSR NVivo 9.
Results: ‘Context’ suggests youth mental health issues are considerably influenced by wider societal context and local factors (e.g. family). Intervention suggests many barriers and enablers to helping young people, be that at the identification, treatment, or engagement stages of intervention.
Conclusions: Many factors influence how a young person develops, seeks help for, and engages with treatment for mental and substance use disorders. This knowledge is useful in developing interventions in primary care that are specific to deprived urban areas.

Volatile organic compounds (VOCs) are found ubiquitously throughout the environment. Benzene, toluene, ethylbenzene, and xylene, a combination also known as BTEX, are common VOCs found indoors. In particular, these compounds can be found in household consumer products such as paints and related organic solvents. Exposure to these compounds has been associated with adverse health effects. Of the BTEX compounds, benzene has been identified as a human carcinogen. Maternal inhalation of benzene may result in fetal exposure through transplacental migration from mother to fetus. To date, the specific mechanism of benzene toxicity remains unknown, but there is enough evidence to conclude that benzene exerts its toxic effects through reactive metabolites. Since pregnant mothers spend much of their time in the household environment, there is the possibility for in utero benzene exposure from indoor paints and paint solvents. Here, a review of VOC and BTEX properties is given, as well as current regulations and components of paints. This information is followed by a risk assessment for in utero exposure to paint fumes containing benzene as a model BTEX compound, using available data regarding human exposure and potential hazards to the fetus. Hazardous exposure of the fetus to paint fumes may occur at the earliest stages of gestation; however...

This thesis presents a new framework for understanding how communities of creators share work, influence one another's creative processes, and learn from one another. I introduce the concept of Online Communities of Creators (OCOCs), which are online communities where the core activity is sharing personal creations. These communities can play an important part in the development of the Creative Society by providing venues for people to encourage each other's creative processes and output. By fostering each other's desires to create and share, these communities help individuals to experience the joy of designing, creating, and sharing. Through these explorations, people develop skills important to their personal development and their ability to participate in the modern workplace. I analyze how ideas spread through OCOCs using the framework for diffusion of innovation developed by Everett Rogers. I map specific behaviors in OCOCs to Roger's five stages of adoption of innovation: awareness, interest, evaluation, trial and adoption. Within OCOCs each of these stages represent deepening understanding of other community members' work. Using a mixed-methods approach of ethnography and social network analysis, I study two specific OCOCs: the Computer Clubhouse Village and the Scratch online community. Both of these communities are designed to facilitate learning with computers. The Village enables members of network of socially-supported computer clubs to share their work...

The purpose of this study was to explore a professional development program that involved 15 teachers. Functional thinking was used as a centerpiece of the program for work with teachers of Grades 1-5 during 6 months of the study. We used the concern-based adaptation model (CBAM) as a methodology to track the process of change of teachers and to understand the trajectories through which teachers may progress. Two questions guided the investigations: 1. How does implementation of the professional development program focused on functional thinking impact teachers' concerns? 2. How did teachers' practice change due to the implementation of the innovation program? The result of the study showed effectiveness of process of change in teachers, both in stages of concerns and level of use of the innovation.

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardant chemicals that are added to plastics, electronic components, furniture foam, and textiles to reduce their combustibility. Of the three commercial mixtures historically marketed, only DecaBDE, which is constituted almost entirely (~97%) of the fully brominated congener decabromodiphenyl ether (BDE-209), continues to be used in the U.S. today. While decaBDE is scheduled for phase-out in the U.S. at the end of 2013, exposures to BDE-209 and other PBDEs will continue into the foreseeable future as products that contain them continue to be used, recycled, and discarded. In addition, decaBDE use continues to be largely unrestricted across Asia, although restricted from use in electronic equipment in Europe.

Despite limits placed on PBDE uses, they are ubiquitous contaminants detected worldwide in humans and wildlife. Major health effect concerns for PBDEs come largely from evidence in laboratory rodents demonstrating neurotoxicity, reproductive and developmental impairments, and thyroid disruption. The potential for PBDEs, particularly BDE-209, to disrupt thyroid regulation and elicit other toxic outcomes in fish is less clear. Thus, the overall objective of this thesis research was to answer questions concerning how fish...

EXECUTIVE SUMMARY
Policy Question
In the context of the Affordable Care Act, what factors create financial burden for female breast cancer patients eligible for Medicare? Specifically, how can LIVESTRONG, a leading cancer advocacy organization, minimize the individual burden from out-of-pocket costs?
Recommendations
The goal of this study was two-fold: 1) develop recommendations to target LIVESTRONG ‘s research about the practical concerns of survivorship, and 2) improve the effectiveness and impact of LIVESTRONG’s navigation services. Correspondingly, my recommendations are separated into these two categories. Past research on patient-provider communication, medical decision-making, and cost-effectiveness precede this work.
All recommendations were evaluated using the criteria of minimizing implementation costs, and maximizing collaboration and buy-in among stakeholders, and maximizing applicability to clients of diverse backgrounds.
Further Research
1. Conduct market research to develop a segmented approach to assist different client groups. OOP costs are a universal challenge. However, different types of individuals (age, gender, race, socio-economic position, insurance type, etc.) access information in different ways. These groups likely have different coping strategies and varying comfort levels in discussing costs. The Medicare population in this study...

Although in its infancy, the field of e-mental health interventions has been gaining popularity and afforded considerable research attention. However, there are many gaps in the research. One such gap is in the area of attrition predictors at various stages of assessment and treatment delivery. Objective: This exploratory study applied univariate and multivariate analysis to a large dataset provided by the Anxiety Online (now called Mental Health Online) system to identify predictors of attrition in treatment commencers and in those who formally withdrew during treatment based on 24 pretreatment demographic and personal variables and one clinical measure. Methods: Participants were assessed using a complex online algorithm that resulted in primary and secondary diagnoses in accordance with the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR). Those who received a primary or secondary diagnosis of 1 of 5 anxiety disorders (generalized anxiety disorder, social anxiety disorder, obsessive-compulsive disorder, posttraumatic stress disorder, and panic disorder) were offered an online 12-week disorder-specific treatment program. Results: Of 9394 potential participants, a total of 3880 clients enrolled and 5514 did not enroll in one of the treatment programs following the completion of pretreatment assessment measures (pretreatment attrition rate: 58.70%). A total of 3199 individuals did not formally withdraw from the 12-week treatment cycle...

Fonte: London School of Economics and Political Science ThesisPublicador: London School of Economics and Political Science Thesis

Tipo: Thesis; NonPeerReviewedFormato: application/pdf

Publicado em //1990EN

Relevância na Pesquisa

55.52%

Estimates of the costs involved in the development of a software product and the likely risk are two of the main components associated with the evaluation of software projects and their approval for development. They are essential before the development starts, since the investment early in software development determines the overall cost of the system. When making these estimates, however, the unknown obscures the known and high uncertainty is embedded in the process. This is the essence of the estimator's dilemma and the concerns of this thesis. This thesis offers an Effort Estimation Model (EEM), a support system to assist the process of project evaluation early in the development, when the project is about to start. The estimates are based on preliminary data and on the judgement of the estimators. They are developed for the early stages of software building in which the requirements are defined and the gross design of the software product is specified. From these estimates only coarse estimates of the total development effort are feasible. These coarse estimates are updated when uncertainty is reduced. The basic element common to all frameworks for software building is the activity. Thus the EEM uses a knowledge-base which includes decomposition of the software development process into the activity level. Components which contribute to the effort associated with the activities implemented early in the development process are identified. They are the size metrics used by the EEM. The data incorporated in the knowledge-base for each activity...

Fonte: South African Journal of SciencePublicador: South African Journal of Science

Tipo: Artigo de Revista CientíficaFormato: text/html

Publicado em 01/01/2012EN

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45.52%

The repeated use of phosphine over decades for the control of the cigarette beetle (Lasioderma serricorne), a significant stored-product insect worldwide, has led to serious negative effects, including strong insecticide resistance, disruption of biological control by natural enemies, and environmental and human health concerns. As an environmentally friendly alternative to synthetic pesticides, plant-derived pesticides have been the focus of much research. We investigated the fumigant activity of whole plant extracts of Elsholtzia stauntonii, a Chinese mint shrub, against the adult, larval, pupal and egg stages of L. serricorne. E. stauntonii extracts exhibited strong fumigant toxicity against L. serricorne; larvae and adults were more susceptible to this toxicity than were eggs and pupae. The toxicity significantly increased with increasing dosage. The corrected mortality of larvae, adults, pupae and eggs reached 99.32%, 97.97%, 44.67% and 33.33%, respectively, at a dosage of 40 μΙ^/Τ air after 48 h of exposure. The declining order of susceptibility of different developmental stages of L. serricorne to E. stauntonii extracts, as indicated by the concentration at which 50% of the insects died (LC50), was as follows: larvae (LC50= 8.82 air)...